This invention relates to a process for preparing detergent compositions, in particular compositions suitable for use in automatic dishwashing machines and having relatively low levels of phosphate builders.
Detergent compositions of the above type are conventionally prepared by an agglomeration process wherein a dry mix of solid, hydratable ingredients is formed and is sprayed or otherwise contacted with water or an aqueous solution of other ingredients to form a granular product. Typical processes of this type are described in U.S. Pat. No. 3,598,743, issued Aug. 10, 1971 to K. Coates, U.S. Pat. No. 3,888,781, issued June 10, 1975 to Kingry and Lahrman, and U.S. Pat. No. 3,625,902, issued Dec. 7, 1971 to Summer.
The above patents refer to the desirability of obtaining a product which is free-flowing and resistant to caking. Traditionally, there have been problems in preparing such agglomerated compositions which were non-caking and which had good carton storage stability. While the processes of the above patents provide a product having acceptable caking properties, these patents are generally concerned with products having high levels of hydratable builder salts, especially sodium tripolyphosphate. In recent years, there has been some concern over environmental problems associated with phosphates in detergents, and it is therefore desirable that phosphate levels in detergents of this type be reduced. Unfortunately, it has been found that reduction of the level of hydratable materials such as sodium tripolyphosphate leads to an increase in the severity of the caking problem with agglomerated detergent compositions.
Accordingly, it is an object of the present invention to provide a process for preparing a free-flowing, non-caking detergent composition. It is a further object of the invention to provide a process for preparing an agglomerated detergent composition having a relatively low level of phosphate builder salts.
Another object of the invention is to produce a non-caking automatic dishwashing detergent composition.